Thermostat setup on existing relay

I have a 5070THBPG (the thermostat with no built in relays) which I am trying to set up to control my simple Hydronic Heating system.
I have an existing 12 channel relay and I am trying to use one of the spare channels to 'call for heat' but as the relay is set up for lighting (for the other channels use) it will not let me add the heating group to that relay.
Is there any way around this or will I have to get another relay just for this?

 

C-Bus Relay units can only be on a single C-Bus Application.

If you've only got 1 or 2 channels to control, you could save a few bucks by buying a 5102RVF instead of a DIN Rail Relay unit. If the inputs to your Hydronic system are ELV (less than 30V ac/dc) then you could buy a 5108RELVP ELV relay unit instead of a DIN Rail Relay unit.

 

Alternatively change the thermostat application to Lighting on the Unit Identification tab and toolkit will create the plant control groups for you.

 

Thanks for the advice.
Is there any major disadvantage to changing the thermostat to a lighting application to allow it to use the existing relay. I have several free channels and would like to save a little by not having to buy another relay for this if possible (project seems to be spiralling as usual!).
However, if it is better to put it on a seperate relay I will, just let me know (will bow down to your expert advice as I am a noob on this and still learning!).

 

And then where do you mount the rotten thing. You build a system with all din rail mount units that mount nicely in cabinets etc and then you need to add some awkward shaped unit somewhere.

Come on Clipsal - when are we going to get a din rail mount 2module 1 & 2 channel relay?

Mick

 

Couldn't agree more. And how about support for multiple applications in output devices. Really should have been supported on the newly released ELV relay unit.

On the subject of mixing lighting and thermostat function on one relay unit, fine if the heating is switching main voltages, but if the heating is low voltage buy an ELV relay unit and use the spare channel to water the garden of something. (Oh dear, now we're back to the single application dilemma ).